Spontaneous formation of gold nanoparticles on MoS2 nanosheets and its impact on solution-processed optoelectronic devices

Spontaneous Decoration of Ultrasmall Pt Nanoparticles on Size‐Separated MoS2 Nanosheets

“…This leads to Pt deposition on the nanosheet surface, without the need for an additional reducing agent [23] . Using this protocol, Au nanoparticle decoration through spontaneous reduction by MoS 2 have also been demonstrated [12a,13a,c] . The MoS 2 nanosheets therefore act not only as a reducing agent, but also as a scaffold to support the reduced metal atoms which grow in to nanoparticles.…”

Tunable Band Alignment of Phase-Engineered Two-Dimensional MoS2 Monolayers

“…Two-dimensional (2D) nanomaterials have received numerous attention over the past decade owing to their superior characteristics including atomic thickness, high mobility, optical transparency, and mechanical flexibility. − Transition metal dichalcogenide (TMD), a class of 2D nanomaterials comprising a layer of transition metal atom that is placed in the middle and two layers of chalcogen atom as a monolayered TMD, has been studied for diverse applications such as field-effect transistor, photodiode, electrochemical catalysis, and optoelectronic devices. − TMD nanomaterials can be synthesized by several approaches in general, which are top–down approaches such as chemical and mechanical exfoliation methods and bottom–up growth methods such as chemical vapor deposition. ,− Among various methods, the intercalant-based exfoliation has been considered as a potent method to obtain high-quality monolayer nanosheets with solution-processable mass production and high yield, where each layer of TMD nanomaterial held by van der Waals interaction can be separated into monolayers from its bulk powder using intercalants. ,, Furthermore, the phase structures of TMDs (1T’- and 2H-phase) can be altered by destabilizing metal coordination via thermal annealing treatment, where TMD with a 2H-phase structure exhibits semiconducting properties based on the trigonal prismatic coordination of the metal atom having hexagonal symmetry, whereas TMD in the 1T’-phase structure exhibits metallic properties based on the distorted octahedral coordination of the metal atom. , Since the phase transition of TMDs by changing their crystal structure can lead to the variation in the electrical, optical, and catalytic properties, as well as energy band structures; thus, the phase-engineered TMDs have the potentials for optoelectronic devices, where the 1T’-phase TMD can generate a much higher total photocurrent compared to that of 2H-phase TMD due to the reduced Schottky barrier height in the optoelectronic devices. , Also, phase-engineered TMDs have been demonstrated for diverse applications such as electronic devices, thin-film transistors, biomedical applications, and energy-harvesting devices. ,,, Considering that the phase-engineered TMDs with van der Waals interactions without dangling bonds have the potential for constructing high-performance electronic and optoelectronic applications, it is necessary to predict the energy band structures as well as band alignments of phase-engineered TMDs to develop optoelectronic applications with improved light absorption and photo responsivity. Previously, several studies have demonstrated the band alignments of the van der Waals interfaces such as 2H-phase molybdenum disulfide (MoS 2 )/graphene oxide, 2H-phase tungsten diselenide/gallium nitride (GaN), 2H-phase MoS 2 /hexagonal boron nitride (h-BN), and 2H-phase tungsten disulfide/h-BN, where all...…”

Molybdenum Disulfide-Assisted Spontaneous Formation of Multistacked Gold Nanoparticles for Deep Learning-Integrated Surface-Enhanced Raman Scattering

“…Therefore, we propose a label-free SERS biosensing platform with high performance achieved through the spontaneous deposition of large-area, multistacked plasmonic nanoparticles on a molybdenum disulfide (MoS 2 ) substrate using a simple electroless plating process without additional pretreatment steps. MoS 2 , a 2D structured semiconductor from the transition-metal dichalcogenides group, has received significant attention across various fields. − Recently, many biosensing studies using a combination of particles and MoS 2 materials have been conducted; however, they are predominantly constrained to the observation of localized areas. − In electrochemistry, electrons are efficiently transferred using the Fermi energy ( E F ) of semiconductors and the redox potential ( E redox ) of electrolytes. − Based on this concept, some studies have been reported to use the equilibrium of the E F of MoS 2 and the E redox of tetrachloroaurate ion (AuCl 4 – ) to spontaneously transfer electrons and reduce gold ions, leading to the formation of AuNPs. − However, a large-scale, 3D close-packed AuNP platform with a MoS 2 substrate has not been developed yet.…”